Rocker centering device



-April 3, 1934. J. c. TRAVILLA, JR., ET AL ROCKER CENTERING DEVICE Filed Sept. 14, 1931 dames C Fay/'lla Jl: [ina/- Hal/guiar* @5 9 Patented Apr. 3, 1934 PATENT olf-'Fics ROCKER CENTERING DEVICE James C. Travilla, Jr., Einar G. Hallquist, E to General Steel Castin City, Ill., a corporation Application September 14 4 Claims.

The invention relates to railway rolling stock and particularly to centering devices for pivotal trucks.

The main object of the invention is to provide simple and inexpensive construction of a rocker type of centering device for a locomotive which will tend to prevent derailment of the truck when the locomotive travels on a curved irregular track at normal speed and at slow speed.

When a vehicle travels on a straight track, or on a curved track, having both the inner and outer rails on the same level, the weight of the vehicle is distributed substantially equally to both of the rails. When the vehicle travels at normal speed on a superelevated curved track the inclination of the track tends to throw an increased portion of the weight of the vehicle on the inner rail and a decreased portion of the weight on the ,outer rail, but centrifugal force of the vehicle rounding the curve counteracts this tendency and the weight on the wheels is thereby equalized substantially.

However, when the vehicle travels slowly along a superelevated curved track, the inclination of the vehicle distributes an unequal portion of the weight of the vehicle to the inner rails Without any counteracting tendency and an excessive lateral resistance is applied to the flanges of the outer wheels, relative to the weight on the latter, or, in other words, there is a decrease in the ratio between the weight on the outer wheels and the lateral resistance at the outer rail which tends to derail the truck. This tendency may result in the entire load being transferred to the rocker on the inner lower side of the curve if the vehicle is a locomotive with the usual spring equalizing systems at each side connected by a cross equalizer suspended from the rear ends of the equalizing systems as illustrated in Patents 1,381,498 and 1,788,588. It is another object of the invention to provide a means for counteracting this derailing tendency.

These and various other detail objects are attained by providing a rocker centering device arranged so that when the load is 100% on the inner rocker, substantially no lateral resistance is applied to the flanges of the outer wheels by the centering device, or, in other words, theratio between the weight on the outer wheels and the lateral resistance at the outer rail is increased as compared with the ratio obtained with the usual centering device, which tends to prevent derailment of the truck.

Figure 1 is a detail transverse vertical section through the rear end of a railway locomotive connecting the side members 2 of a railway loco- Philadelphia, Pa., and ardsvlle, Ill., assignors gs Corporation, Granite of Delaware 1931, Serial No. 562,796

frame and pivotal truck and centering of the type referred to the elements of the centering device being in their normal positions.

Figure 2 is similar to Figure 1 excepting travel of the vehicle is indicated along a highly superelevated curve and the rocker element of the centering device being shown in a rotated position relative to its bearings.

Figure 3 is an end View of a modied form of the centering device.

Figure 4 is an end view of another modif-led form of the centering device.

In the particular structure illustrated in Figures 1 and 2, 1 indicates a transverse member motive trailer truck tted with journalled wheels 3 and traveling along the rails 4. Rocker seat bearing 5 is detachably mounted on the side member 2 and positioned thereon by means of its downwardly projecting dowels 6 inserted through the openings 7 in the upper face of the side member 2. Rocker seat 8 is in turn mounted upon its bearing 5 and secured in position thereon by means of the overhanging integral lugs 9. The upper portion of rocker seat 8 is provided with longitudinally extending grooves 10 and 11 which are substantially semi-circular in section.

Bearing plate 12 is provided on the underside of the locomotive frame 13 and interlocked therewith in a position adjacent to therside member 2 of the truck frame. The under surface of the bearing plate 12 forms an inverted obtuse dihedral angle having its outer side horizontal, and the apex of the inclined surface extending radially of the pivotal center of the truck or substantially longitudinally of the locomotive frame.

The rocker member 16 is interposed between the seat Sand bearing plate 12 to support the 1ooomotive frame. Parallel trunnion bearings 17 and 17a of substantially circular section are provided on the rocker 16 and function as pivots therefor and are journalled in the grooves 10 and 11 of the rocker seat 8.

Depending lugs 14 and 15 are provided transversely of the horizontal and inclined surfaces 100 of the bearing plate 12 and are inserted in openings in the top of the rocker 16 to retain the rocker in position relative to the bearing plate 12 irrespective of frictional contact between the bearing plate andthe rocker. The upper flanged surface of the rockers 16 comprises two intersecting curved portions 18 and 18a, the radial centersof which being the centers of the trunnion bearings 17 and 17a respectively. For a purpose which will be hereinafter more fully explained the inner trunnion bearing 17 is lower than the outer one 17a.

In Figure 1, illustrating the kvehicle traveling along a straight track with all of the associated parts in their normal positions, the rockers 16 will have Ythe greatest stability, that is, gravity reacts vwith the yweight of the locomotive frame and with each rocker supported on both of its trunnion bearings and the lugs 14 and 15 of the locomotive frame bearing plate 12 engaging the rocker to hold it against rotational movement from its normal position.

When the rockers 16 are oscillated, there is a traveling or rotational engagement between the upper surfaces and the bearing plates 12 which is made more positive by means of the lugs 14 and 15 engaging with the perforated bearing surfaces of the rockers, and a rotational engagement between one or the other of the trunnion bearings 17 and 17a with its respective journal seat.

Whenrthe vehicle travels along a curve, there is a thrust of the iianges of the truck wheels, at the outside of the curve, against the outer rail of the track, due to the tendency of the wheels to travel at a tangent to the curve and due to the outward movement of the adjacent portion of the locomotive frame which is positioned by the other wheels, and due to centrifugal force, and the outer rocker 16 is rotated on its journalled trunnion bearing 17a and rides on the inclined surface portion of the corresponding bearing plate 12 and thrusts the rocker and adjacent truck frame downwardly .oy compressing the truck springs and this produces a tendency to keep the outer wheels of the truck on the rail. On the opposite side of the vehicle, over the inner curved rail, the inner rocker 16 will be rotated on its journalled trunnion bearing 17 and engagement between the rocker surface 18 and the adjacent normally horizontal portion of plate 12 and this arrangement will permit lateral displacement vwithout substantial lateral resistance.

It is apparent that during this displacement of the locomotive frame, the outer rocker is tilted on one trunnion so that the weight is applied to the rocker out of vertical alinement with its trunnion and this serves as a centering force tending to return theassociated parts to their normal centralized positions where the vehicle leaves the curved track and enters straight track.

t is also apparent,` and the main advantage in this form of the invention over previous rocker type of centering devices is, that substantially all of the lateral resistance of the truck to movement relative to the locomotive frame due to the centering device is produced by the centering device over the outer rail and that substantially no resistance is produced by the centering device over the inner rail when the vehicle is on a curve. As the greater load is on the inner rail of an .elevated curve when the vehicle is run slowly and as the centering device on this sideY produces substantially no resistance to lateral movement, the total resistance against the iiange of the outer wheel will be less than when the vehicle is lrun at a speed which increases the load on the4 outer wheel due to the centrifugal force of the load, and thus the tendency for .derailment of the vehicle will be greatly reduced whether it is run at normal speed or a slow speed.

'Another advantage in this form of the invention is that the elements of the centering devices used on both sides of the vehicle are symmetrical and interchangeable.

In Figure 3, a modification of the centering device is illustrated comprising a rocker seat 20, a rocker 2l, and a rocker bearing plate 22. In this structure the rocker and seat are of the same design as those described in the structure illustrated in Figures l and 2 but the under portion of the bearing plate 22 forms an inverted obtuse angle, both sides of which being inclined with respect to the horizontal, and is provided Vwith transversely extending depending lugs 23 vand 24.

In this form of the centering device, the elements of the centering device are mounted and function in a manner similar to that in the first mentioned form, and the resistance to the lateral motion of the vehicle frame is greater than that produced in the first mentioned orin due to the outer bearing portion of the rocker plate being inclined whereas in the rst mentioned form of the centering device, the outer portion of the rocker plate is horizontah Obviously, in both forms of the centering device, the resistance oiiered by the surface on the outside of the rocker plate is less than that offered by the surface on the inside of the rocher plate.

Similarly too in this form of the invention the elements of the centering devices used en both sides of the vehicle are symmetrical and interchangeable as well as their relative positions being reversible.

In both forms of the invention, in order to minimize the slippage between the rocker face and the bearing surfaces on the rocker plate, the rocker trunnion bearings in the rocker seat are located at different levels. The same initial and constant resistance against lateral movement of the vehicle frame in either direction is provided because the points of Contact of each rocker with the surfaces on the rocker plate are at the intersections therewith of the lines X and Y perpendicular to the surfaces on the rocker plate and passing through the centers of the respective trunnion bearings.

In Figure 4, another modiiication of the centering device is illustrated comprising a rocker seat 25, a rocker 26, and a rocker bearing plate 27. In this structure the rocker is provided with a single pivotal bearing 28 and a single curved top bearing surface 29, the radial center of which being the center of the pivotal bearing 28. The rocker bearing plate 27 is similar to the plate 12 shown in Figure l, however, a plate similar to 22 as shown in Figure 3 may be used if desired. This arrangement also provides for the same initial andconstant resistance against lateral movement of the vehicle frame in either direction, the same as the structures shown in Figures 1, 2, and 3, because the points of contact of the rocker with the lsurfaces on the rocker plate are at the intersections therewith of the lines X and Y perpendicular to the surfaces on the rocker plate and passing through the center of the bearing 28.

Obviously various features and details herein disclosed may be modified without departure from the spirit of the invention and the exclusive use of all features coming within the scope of the claims is contemplated.

What is claimed'is:

1. In combination, a railway vehicle frame and a pivotal truck, and a centering device on each side of said truck, each device comprising a movable member interposed between upper and lower Vbearing elements, said upper bearing element being mounted on said vehicle frame and said lower bearing element being mounted on said pivotal truck, the lower of said bearing elements having spaced recesses therein, said movable member having spaced projections located at different levels, while in normal position, and adapted to be journalled in said recesses, and having a perforated bearing surface comprising two curves of equal radii, the radial centers of which being the centers of said spaced projections, the other of said bearing elements having a bearing surface comprising an inner portion and an outer portion relative to the longitudinal center line of the vehicle, said portions forming an obtuse dihedral angle and having projections thereon, said movable member being pivotal about the center of either of its spaced projections, and having its curved bearing surface in contact with that surface portion of the obtusely angledbearing element opposite to the movable member pivot to support the vehicle frame and to resist the lateral movement of the truck relative to the vehicle frame, said projections on said bearing element cooperating with the perforated bearing surface of said movable member to ensure positive rotational movement of the latter on said bearing element.

2. As an assembled article of manufacture, a centering device comprising a journal element, a bearing plate and an interposed movable rocker element, said journal element having a bearing surface on one side provided with substantially semi-circular shaped grooves, the center lines of which being at diiferent levels and disposed substantially longitudinally of said element, and having on its opposite side means for interlocking said element with an associated vehicle member, said bearing plate having an obtusely angled bearing surface, and said movable rocker element being substantially the shape of a circular sector having a curved bearing surface of equal radii but of diiferent radial centers and provided with parallel trunnion bearings equally spaced on either side of the radius intersecting the apex of the sector and being of substantially circular cross-section, the centers of which bearings being at different levels and serving as radial centers for the curved bearing surface, and having the center lines of the trunnion bearings disposed substantially longitudinally of said element, and said rocker element being pivotal about the center of either of its trunnion bearings and journalled in either of said grooves in said journal element and having its curved bearing surface in contact with that portion of the angled bearing surface of said bearing plate opposite to the trunnion about which the rocker is pivoted to support said bearing plate.

3. In a railway truck centering device, a rocker seat comprising a downwardly facing element arranged for mounting on a truck member and an upwardly facing element having substantially semi-circular grooves, the axes of which are at diiferent distances from said downwardly facing element, and a rocker having depending trunnion feet disposed symmetrically relative to the rocker surfaces and seated in said grooves and stably supported therein independently of a load on the rocker.

4. In combination, a railway vehicle pivotal truck and a frame mounted thereon, and a rocking device at each side of said truck for supporting said frame, each of said devices comprising a seating element, with journal bearings spaced apart transversely of the truck and located at different levels, and a rocker with spaced trunnions journaled in said bearings, said rocker being symmetrical about an axis extending intermediate the bearings and bisecting the rocker surface, said rockers being tilted upwardly and inwardly when the truck and frame are in their normal position, there being a horizontal bearing element for riding on each rocker when the same is supported upon its lower journal bearing and a downwardly inclined bearing element for riding on said rocker when it is supported upon its outer journal bearing, whereby when the vehicle is on a curve and the frame moves laterally relative to the truck the centering device at the outside of the curve will increase the distance between the adjacent portions of the frame and truck while the centering device at the inside of the curve will substantially maintain the spacing of the adjacent parts of the frame and truck.

JAMES C. TRAVILLA, JR. EINAR G. HALLQUIST. 

